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US 10,947,876 B2Granted
Air-transparent selective sound silencer using ultra-open metamaterial
AssigneeTrustees of Boston University
InventorsXin Zhang, Reza Ghaffarivardavagh, Stephan Anderson
Life of this patent
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Abstract
A bilayer metamaterial silencer allows substantial fluid through the apparatus, while mitigating the propagation of sound through the apparatus, and while providing a form factor that is significantly more compact than previously-known devices. Moreover, illustrative embodiments allow a designer to specify one or both of the frequency or frequencies at which the apparatus mitigates sound propagation, and/or the bandwidth around the frequency or frequencies at which the apparatus mitigates sound propagation.
Claims28
An apparatus comprising:
- a first channel having a first inlet and a first outlet, the first channel open to propagation of a first wave at a target frequency therethrough and having a first area in cross-section, and
- one or more second channels each open to the propagation of a second wave at the target frequency therethrough, and each having a second inlet and a second outlet, the one or more second channels defining a second area in cross-section,
- wherein each of the one or more second channels is disposed relative to the first channel such that the second wave at the target frequency exiting the one or more second outlets is capable of destructively interfering with the first wave at the target frequency exiting the first channel, and
- wherein the first area in cross-section is larger than the second area in cross-section such that the apparatus has an openness ratio of at least 0.8.
1 more element
An apparatus comprising:
- a first channel open to the propagation of a first wave at a target frequency therethrough, and having a first inlet and a first outlet, the first channel configured to remain in a continuum state during propagation of the first wave therethrough;
- and one or more second channels each having a second inlet and a second outlet, the one or more second channels extending along an axis defining an axial direction, and open to propagation of a second wave at the target frequency therethrough, each of the one or more second channels configured to resonate at the target frequency;
- wherein the one or more second outlets open in the axial direction, and wherein the one or more second channels is disposed, relative to the first channel, such that the second wave at the target frequency exiting the one or more second outlets is capable of destructively interfering with the first wave at the target frequency exiting the first channel.
An apparatus comprising:
- a first channel open to the propagation of a first wave at a target frequency therethrough, and having a first inlet, and a first outlet opening into an un-ducted volume,
- one or more second channels, each extending along an axis and open to the propagation of a second wave at the target frequency therethrough, each having a second inlet, and a second outlet opening into the un-ducted volume;
- wherein the one or more second channels is disposed, relative to the first channel, such that the second wave at the target frequency exiting the one or more second outlets is capable of destructively interfering with the first wave at the target frequency exiting the first channel.
An apparatus comprising:
- a first channel open to propagation of a first wave at a target frequency therethrough, and having a first inlet and a first outlet, wherein the first channel is configured to remain in a continuum state in the presence of a wave at the target frequency;
- one or more second channels, each open to propagation of a second wave at the target frequency therethrough and configured to resonate at the target frequency, and each having a second inlet and a second outlet;
- wherein each of the one or more second channels is disposed, relative to the first channel, such that the second wave at the target frequency exiting the one or more second outlets is capable of destructively interfering with the first wave at the target frequency exiting the first channel.
Dependencies are inferred from the claim text.